Featured Research

from universities, journals, and other organizations

How Mosquitoes Avoid Succumbing To Viruses They Transmit

Date:
December 3, 2008
Source:
Virginia Tech
Summary:
Mosquitoes can spread viruses which cause disease without themselves getting sick. Scientists long thought that the mosquito didn't care whether it had a virus hitchhiker, but have now discovered, "there is a war going on" at the cellular level, between the host and invading RNA -- the strands of code that produce different kinds of viral proteins.

Mosquitoes are like Typhoid Mary. They can spread viruses which cause West Nile fever, dengue fever, or yellow fever without themselves getting sick. Scientists long thought that the mosquito didn't care whether it had a virus hitchhiker, but have now discovered, "There is a war going on," said Zach Adelman, assistant professor of entomology at Virginia Tech.

The war is at the cellular level, between the host and invading RNA – the strands of code that produce different kinds of viral proteins.

The mediators that balance the interactions between mosquito and virus are virus-derived short-interfering RNAs (viRNAs), which are generated by the mosquito's immune response to infection. "If the mosquito is not able to cut up the virus genome into viRNAs, an otherwise invisible infection becomes fatal-- for both the mosquito and the virus. In other words, to complete the circle and be transmitted back to a vertebrate host, the virus must submit, to some extent, to the mosquito's antiviral response," said Kevin M. Myles, assistant professor of entomology at Virginia Tech.

Myles, Adelman, and their Ph.D. students, who are with the Vector-borne Disease Research Group at Virginia Tech, report their findings about the war between the mosquito immune system and viruses in the Proceedings of the National Academy of Sciences (PNAS), scheduled to appear in the Online Early Edition the week of December 1-5, 2008. The article is, "Alphavirus derived small RNAs modulate pathogenesis in disease vector mosquitoes," by Myles; Michael R. Wiley of Ambler, Pa.; Elaine M. Morazzani of Vienna, Va.; and Adelman.

"We asked, "How is it that the mosquito can control the pathogenicity of these viruses so well, while humans with our more complex immune systems, often develop disease when infected?" said Myles.

The researchers used the arthropod-borne virus Sindbis -- a model virus for a wide variety of mosquito-transmitted viruses, such as chikungunya and eastern equine encephalitis, both of which cause serious diseases in humans. They infected a mosquito called Aedes aegypti, an important vector of yellow fever and dengue. In response, the mosquito immune system generated viRNAs, which make up 10 percent or more of total cellular small RNAs. "The proportion of the small RNAs that are viRNAs was surprising," the article states.

The researchers then altered the Sindbis genome so that it would carry a protein known to suppress the ability of a cell to cut up virus genomes into viRNAs. "We can't yet knock-out the mosquito's immune response, so we had to alter the virus," Adelman said.

The research also represents the first application of next generation high-throughput sequencing to characterize small RNAs from mosquitoes infected with an arbovirus – a virus that is transmitted by an arthropod vector , said Myles. The researchers used an Illumina machine capable of generating more than four million sequences from one sample. "It is powerful technology," said Myles.

The discovery provides a potential target for fighting mosquito-borne diseases – by upsetting the balance so the virus kills the mosquito. "We didn't know it was possible to unleash this kind of pathogenic potential in the mosquito," Myles said.

"We would still have mosquitoes biting us, but they would not be transmitting viruses," said Adelman.

Additional research will be required to determine how to manipulate the mosquitoes' immune response towards this end," said Myles.

The paper also discusses the potential of therapeutic approaches using knowledge gained from studying viRNAs from infected mosquitoes to control the pathogenesis of these viruses in mammalian hosts.


Story Source:

The above story is based on materials provided by Virginia Tech. Note: Materials may be edited for content and length.


Cite This Page:

Virginia Tech. "How Mosquitoes Avoid Succumbing To Viruses They Transmit." ScienceDaily. ScienceDaily, 3 December 2008. <www.sciencedaily.com/releases/2008/12/081201195941.htm>.
Virginia Tech. (2008, December 3). How Mosquitoes Avoid Succumbing To Viruses They Transmit. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2008/12/081201195941.htm
Virginia Tech. "How Mosquitoes Avoid Succumbing To Viruses They Transmit." ScienceDaily. www.sciencedaily.com/releases/2008/12/081201195941.htm (accessed July 25, 2014).

Share This




More Plants & Animals News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Boy Attacked by Shark in Florida

Boy Attacked by Shark in Florida

Reuters - US Online Video (July 24, 2014) An 8-year-old boy is bitten in the leg by a shark while vacationing at a Florida beach. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Goma Cheese Brings Whiff of New Hope to DRC

Goma Cheese Brings Whiff of New Hope to DRC

Reuters - Business Video Online (July 24, 2014) The eastern region of the Democratic Republic of Congo, mainly known for conflict and instability, is an unlikely place for the production of fine cheese. But a farm in the village of Masisi, in North Kivu is slowly transforming perceptions of the area. Known simply as Goma cheese, the Congolese version of Dutch gouda has gained popularity through out the region. Ciara Sutton reports. Video provided by Reuters
Powered by NewsLook.com
Dogs Appear To Become Jealous Of Owners' Attention

Dogs Appear To Become Jealous Of Owners' Attention

Newsy (July 23, 2014) A U.C. San Diego researcher says jealousy isn't just a human trait, and dogs aren't the best at sharing the attention of humans with other dogs. Video provided by Newsy
Powered by NewsLook.com
Professor Creates Site Revealing Where People's Cats Live

Professor Creates Site Revealing Where People's Cats Live

Newsy (July 23, 2014) ​It's called I Know Where Your Cat Lives, and you can keep hitting the "Random Cat" button to find more real cats all over the world. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile: iPhone Android Web
          Follow: Facebook Twitter Google+
          Subscribe: RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins